How to write partition for quicksort with c++?

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int partition(int arr[], int low, int high) {
    int pivot = arr[high]; // Select the pivot element (you can choose any element as pivot)
    int i = low - 1; // Index of the smaller element

    for (int j = low; j < high; j++) {
        if (arr[j] < pivot) {
            i++;
            // Swap arr[i] and arr[j]
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }

    // Swap arr[i + 1] and arr[high] (or pivot)
    int temp = arr[i + 1];
    arr[i + 1] = arr[high];
    arr[high] = temp;

    return i + 1; // Return the partition index
}